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arm64/signal: Don't assume that TIF_SVE means we saved SVE state

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commit 61da7c8e2a602f66be578cbbcebe8638c10e0f48 upstream.

When we are in a syscall we will only save the FPSIMD subset even though
the task still has access to the full register set, and on context switch
we will only remove TIF_SVE when loading the register state. This means
that the signal handling code should not assume that TIF_SVE means that
the register state is stored in SVE format, it should instead check the
format that was recorded during save.

Fixes: 8c845e273104 ("arm64/sve: Leave SVE enabled on syscall if we don't context switch")
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240130-arm64-sve-signal-regs-v2-1-9fc6f9502782@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mark Brown 2024-01-30 15:43:53 +00:00 committed by Greg Kroah-Hartman
parent 4796a1a413
commit 60480c6bc1
2 changed files with 3 additions and 3 deletions
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2
arch/arm64/kernel/fpsimd.c
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@ -1686,7 +1686,7 @@ void fpsimd_preserve_current_state(void)
void fpsimd_signal_preserve_current_state(void)
{
fpsimd_preserve_current_state();
if (test_thread_flag(TIF_SVE))
if (current->thread.fp_type == FP_STATE_SVE)
sve_to_fpsimd(current);
}

4
arch/arm64/kernel/signal.c
View File

@ -242,7 +242,7 @@ static int preserve_sve_context(struct sve_context __user *ctx)
vl = task_get_sme_vl(current);
vq = sve_vq_from_vl(vl);
flags |= SVE_SIG_FLAG_SM;
} else if (test_thread_flag(TIF_SVE)) {
} else if (current->thread.fp_type == FP_STATE_SVE) {
vq = sve_vq_from_vl(vl);
}
@ -878,7 +878,7 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
if (system_supports_sve() || system_supports_sme()) {
unsigned int vq = 0;
if (add_all || test_thread_flag(TIF_SVE) ||
if (add_all || current->thread.fp_type == FP_STATE_SVE ||
thread_sm_enabled(&current->thread)) {
int vl = max(sve_max_vl(), sme_max_vl());